There are so many voices out there that are insistent on having back up iron sights. Batteries die! Electronics fail! EMPs! Lightning strikes! Bear attacks!!!! Yet, I have rarely seen the realities of using them discussed or put to print. It makes me wonder if most people have even tried shooting with their back up iron sights.
The issue is that the performance of back up iron sights can be radically affected by factors external to the sights themselves. A long time ago on JTT, we posted an article about how using your back up iron sights through an optic like an RDS can change your zero. More recently, we posted about how something as simple as changing your eye protection can change your zero. This zero shift phenomena has most recently been noted by Ivan at Kit Badger on his blog and in an accompanying video (this article and video are well worth checking out).
Back up iron sights have become something of a panacea, inducing those who have them on their rifles to believe that they are prepared for an optic failure. However, as is often the case with gear, there are some planning and training considerations that need to be worked out to get the most out of them (or make them work at all).
Back up iron sights are a good idea if you have zeroed them in the exact way that you plan to use them. If you zeroed your back up iron sights through your optic, they will not be zeroed with the optic removed and vice versa. The shift can be dramatic and noticeable over distances as short as 10 yards. This is why planning is a must.
You will not be able to use your back up sights through a magnified optic or a prism sight which dictates that they must be zeroed and used with the optic removed. This means that the issue being discussed in this article is mostly (or maybe completely) applicable to the use of back up sights with non-magnified optics like red dots. The type of optic you have, the type of mount it is in (QD or not), and other factors will all play a role in your plan to deal with an optic failure.
If you have a quick detach mount, your plan could be to remove the optic in which case you should zero your back up sights with the optic removed. If you do not have a quick detach mount, you will need to zero the iron sights through the optic and probably train techniques like “shooting through the tube” or using your RDS itself as a large rear sight. If you have a magnified optic in a non-QD mount, you may want to forgoe back up irons completely unless you are going to carry whatever kind of tool you need to remove the mount from the rifle. There are a number of factors that drive your plan. If you aren’t happy with your options… Maybe you need to rethink your gear choices.
Here is the bottom line: If you haven’t tested the performance of your back up sights in various applicable situations and come up with a plan to deal with issues that arise from that testing, your back up iron sights probably aren’t as useful as you think they will be.
Excellent article and very valid points.
I would argue for shooting through the tube on a defensive carbine but removing the dot if the gun is never meant to be used defensively (range, hunting, etc).
I would skip irons on a rifle with magnified optics, unless intending for very critical role (subsistence hunting, doomsday survival, etc).
On the other hand, I’ve seen some impressive results with SBRs, so a QD magnified optics would be one way to transition between short and long range configurations. However, I think there are better ways now, such as 1-X variable optics, offset sights, even lasers.
And FWIW, I did have a sight go down recently. It started raining at the range and I decided to wait it out/shoot anyway. The cheap holographic style dot on my plinker was unusable. I actually couldn’t tell if the electronics went down, or if there was just a droplet on the emitter lens, but either way, I couldn’t aim. Since then, I’ve decided to have backup sights when practical.
You might want to reevaluate your stance on BUIS. A quick look at the video shows something that I can replicate, and see, on a range, day in and day out, with experienced law enforcement officers, soldiers & Marines. Consistency is key in accuracy, the fact that the shooter fired a so-so 3 rd group at a very close distance, left his shooting position to check his target, and then went back and repeated the process after removing his optic tells me nothing. Had he done anything remotely reinforcing basic fundamentals for accuracy testing or zeroing (match ammo, bench rest or a bipod, 100 yard target, multiple groups of 5 or preferably 10 rds) all with and without the optic, without going down range and basically having to rebuild his shooting platform upon return, then this might have held my interest. BUIS are incredibly important for those of us who have and who do use them when our optics fail, and if you carry a rifle for a living, it happens far more often than you realize. There are other factors that come into play here that were not even considered. Does glass reflect and bend light? Absolutely! Does parallax exist? You know it does, even with “parallax free” optics. However, I can think of several instances from my 21 yr career in govt service where BUIS allowed an officer/agent/or Marine a chance to immediately dispatch a threat when their respective optic or batteries failed, shut down (4-8hr auto shutoff on EoTechs ring a bell?), or literally rattled loose and fell off the rifle unexpectedly during use.
Paul Howe’s take on irons and optics